The present invention generally relates to sensing and analysis systems and methods, for example, sensing and analyzing properties, conditions, and substances present within the environment, and physiological conditions and substances present within humans. More particularly, this invention relates to sensing and analysis systems, networks, and methods that make use of a sensor unit that is very portable, compact, and operates in combination with a physically separate electronic computational and communication device that can be configured to power and control the sensor unit and process the output of the sensor unit, such that the sensor unit is not required to contain components necessary to carry out these functions. The computational and communication device can be part of a network, optionally containing other sensor units and computational and communication devices, enabling remote communications with the sensor unit including dissemination of its output and remotely-generated instructions.
Chemical and fluid analysis equipment generally sense and analyze a sample of a material (gas, liquid, or solid) for the presence or amounts of constituents within the sample or other physical or chemical properties of the sample. Conventional equipment for performing chemical and/or fluid analysis are typically large, standalone units equipped with a dedicated display, keypad, data processing capability, and control algorithm. These equipment typically consume a considerable amount of power, necessitating an AC power supply for continuous operation, though may be equipped with a large battery for temporary operation when an AC power supply is unavailable. Current equipment are at times equipped to be linked to a computer, such as through an RS-232 serial communications cable, enabling data to be sent to the computer, which can then store, manipulate, and print the raw or manipulated data. The computer may be part of a wireless network, allowing the raw or manipulated data to be communicated to a remote location.
The size, weight, and cost of conventional chemical and fluid analysis equipment limit their ability to be widely used at remote locations where analysis is often necessary, and also limit their ability to be used at multiple locations where sensing and monitoring would be beneficial, such as when monitoring conditions and hazards within the environment. The power consumption requirements for wireless communications is also a significant limitation when attempting to implement wireless sensing equipment on a conventional network. Power consumption limits the distance a wireless sensor can be located from its network receiver, with higher power level requirements necessitating an increase in the size or volume of the wireless sensor node.
Various advancements have been proposed for wireless and wired sensors and sensor networks, examples of which include U.S. Pat. No. 6,338,010 to Sparks et al., C. Hsin et al., “Randomly Duty-Cycled Wireless Sensor Networks: Dynamics of Coverage,” IEEE Trans. On Wireless Communications, Vol. 5, No. 11, p. 3182-3192 (November 2006), K. Wise, “Wireless Integrated Microsystems: Coming Revolution in Gathering of Information,” NSTI Nanotech '06, Boston, Mass., p. 455-458 (May 2006), F. Kocer et al., “A New Transponder Architecture with On-Chip ADC for Long-Range Telemetry Applications,” Journal Solid-St Cir., Vol 41, No. 5, p. 1142-1148 (May 2006), and D. Sparks et al., “Multi-Sensor Modules with Data Bus Communication Capability,” Proceedings of the Spring SAE Conf., No. 1999-01-1277, p. 1 (1999). Nonetheless, there is a continuing need for more versatile sensing and analysis systems, networks, and methods.